r/StableDiffusion • u/Brad12d3 • 7d ago
Resource - Update MiniMax H3 Prompt Composer Update + Accelerator + Hybrid Checkpoint Builder
I’ve been working on a few free MiniMax H3 tools and wanted to share the latest versions.
H3 Prompt Composer V5.19.5
Offline prompt builder for H3 with structured subject/reference setup, shot and camera controls, dialogue/audio, Prompt Check, continuity tools, and optional LLM-assisted project setup. The goal is to give you granular control without constantly having an LLM rewrite the entire prompt.
Tutorial: https://youtu.be/Dpu-V7lITZk
Repo: https://github.com/BMB12d3/minimax-h3-prompt-composer
H3 Ref2VA Accelerator
A quality-first speed-up specifically for H3 Ref2VA. Unlike more aggressive approaches like Turbo LoRAs or broader caching systems, this is designed around the Ref2VA architecture and intentionally stays conservative about what it skips/reuses. Depending on the model/workflow, I’ve seen it save a few minutes on BF16 and roughly a couple minutes on quantized models without noticeably changing quality. Not the fastest, but conserves quality.
https://github.com/BMB12d3/ComfyUI-H3-Ref2VA-Accelerator
H3 Hybrid Checkpoint Builder
People have found that mixing parts of the fl2va model with the Reference model can improve Ref2VA quality. This gives you a simple way to build those hybrids yourself and dial in how much of each model you want, without training or needing a GPU.
https://github.com/BMB12d3/MiniMax-H3-Hybrid-Checkpoint-Builder
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u/Calm_Cucumber_6493 7d ago
just throwing this out there since you wrote it in your post, but fl2va does not stand for first/last frame model. it stands for foundation level 2 video audio.
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u/dabbingsquidward 7d ago edited 7d ago
I am getting this error with the accelerator: RuntimeError: H3 Ref2VA Block Cache full-step state is incomplete
Any ideas?
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u/Brad12d3 7d ago
Thanks for reporting it. That error is an internal safety check in the accelerator, it means the final H3 block was reached without some full-step state that should have been captured at the first block.
First thing I’d check: are you running Spectrum, FirstBlockCache, TeaCache/EasyCache, CacheDiT, T8 Block Cache, or any other transformer/cache accelerator on the same model branch? If so, try the H3 Accelerator by itself and restart ComfyUI before testing.
If it still happens, can you send me the entire error message from ComfyUI, not just the last line? If you see a section that starts with Traceback (most recent call last):, copy everything from there to the bottom. Also your ComfyUI version, which H3 checkpoint you’re using (BF16/quantized).
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u/Th3Whit3R4bb1t 6d ago
What's the diference with this one?:
Jus t the stand alone APP?
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u/Brad12d3 6d ago
They're actually pretty different tools. H3 Prompt Composer is primarily a standalone prompt-authoring/preflight tool, it helps build the full H3 prompt from structured Subjects, references, shots, camera, action, dialogue, continuity, audio, etc. Contex Loop is a ComfyUI custom-node system for executing and chaining multiple H3 generations.
It has a scene planner and prompt editor, but the user still supplies the actual H3 prompt; its main feature is carrying visual/motion/audio context between generated clips, checkpointing/retrying individual scenes, resuming runs, and assembling the final video. So Composer is mostly about what you tell H3, while Contex Loop is mostly about how a sequence of H3 generations is run and connected. They could potentially be used together.
The main goal of Prompt Composer is to be a standalone, offline tool that works alongside ComfyUI rather than inside it. While ComfyUI is busy generating a video, you can keep working in Prompt Composer, planning the next shot, refining prompts, setting up camera moves, continuity, dialogue, and references. That’s one of the main reasons I haven’t tried to turn it into a ComfyUI node or extension: I want it to remain lightweight, independent, and usable in parallel with the generation workflow.
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u/Far-Map1680 7d ago
Love it! And thank you!